Contact elements-Mechanical APDL
 

how to use contact elements in APDL? I need the interface behaviour of steel -concrete composite slab. Contac174 and Target 170 were used in the modelling of steel plate and concrete contact surfaces. But error messages are there like "normal of target element 14446 is not consistent with the normal of target element 14445 ". Around 6000 nodes have the same error.How will I rectify the error? Please help me.